1. Field of the Invention
The present invention relates to an earpiece assembly of a headpiece, and to stethoscopes and other headpieces that include such an earpiece assembly. In a class of embodiments, the inventive earpiece assembly includes an ear tip portion (which directly interfaces with the user's ear canal) configured to be rotatable on axis (about the earpiece assembly's longitudinal axis) relative to the rest of the earpiece assembly and to have limited freedom to pivot off axis (about at least one axis that is perpendicular to the longitudinal axis) relative to the rest of the earpiece assembly.
2. Background of the Invention
Throughout this disclosure, including in the claims, the expressions “headset,” “headpiece,” and “head piece” are used as synonyms to denote an apparatus configured to be worn on or positioned against a user's head. Examples of headsets are the head pieces of stethoscopes (both acoustic (or passive) and active (e.g., electronic) stethoscopes), audio headphones (of the type that include a small loudspeaker for each ear, to make audible the output of a home or portable audio system), and telephone headsets (of the type including a microphone as well as a small loudspeaker for each ear or a single one placed in the lumen structure etc. as mentioned previously).
Throughout this disclosure, including in the claims, the expression “ear piece assembly” (or “earpiece assembly” or “earpiece”) denotes a subassembly (or portion) of a head piece, intended and configured to be positioned in, or otherwise in direct contact with, an ear of the head piece's user. The expression “ear tip” (or “ear tip” portion) herein denotes an element or portion of an ear piece assembly that is intended and configured to be positioned in, or otherwise in direct contact with, an ear of the ear piece assembly's user, and assumes that the ear piece assembly includes at least one other element (or portion) that is not an ear tip. Examples of ear tips include the small loudspeakers (sometimes referred to as sound transducers) of a pair of audio headphones, and the soft ear tips (which generally do not contain transducers) of the head pieces of passive stethoscopes.
Throughout this disclosure, including in the claims, the term “proximal” (with reference to a headpiece) denotes “toward” the center of the head of a user who wears the headpiece, and the term “distal” (with reference to a headpiece) denotes “away from” the center of the head of a user who wears the headpiece. Thus, a “proximal” portion (e.g., “proximal” end) of an earpiece assembly (or a subassembly of an earpiece assembly) denotes a portion of the assembly (or subassembly) located “toward” or relatively near to the center of the head of a user who wears a head piece including the assembly, and a “distal” portion (e.g., “distal” end) of an earpiece assembly (or a subassembly of an earpiece assembly) denotes a portion of the assembly (or subassembly) located “away from” or relatively far from to the center of the head of a user who wears a head piece including the assembly. An ear tip portion of an earpiece assembly is located at the proximal end of the assembly during use.
Throughout this disclosure including in the claims, the expression “active” stethoscope (or “active” sound detection device) denotes a stethoscope (or sound detection device) that includes an acoustic transducer useful for converting acoustic waves (e.g., body sounds of interest) into another form of energy.
Herein, the expression “electronic” stethoscope (or “electronic” sound detection device) denotes a stethoscope (or sound detection device) that includes an acoustic transducer useful for converting acoustic waves of interest (e.g., body sounds) into at least one electric signal. Also herein, the expression “passive” stethoscope (or “passive” sound detection device) denotes a stethoscope (or sound detection device) that does not include an acoustic transducer.
Throughout this disclosure, including in the claims, each of the expressions “acoustic transducer” and “sound transducer” denotes a device for converting acoustic waves into another form of energy. For example, one type of acoustic transducer is a typical microphone configured to convert acoustic waves into an electrical signal. Another example of an acoustic transducer is a device configured to convert acoustic waves into electromagnetic waves (e.g., visible radiation or electromagnetic radiation whose wavelength or wavelengths is or are outside the visible range), and optionally also to convert the electromagnetic waves into an electrical signal. Acoustic transducers are sometimes referred to as sound pick-ups, and are sometime referred to herein simply as transducers.
Throughout this disclosure including in the claims, the expression “axis” of an earpiece assembly (or ear tip), unless otherwise defined, generally assumes that the earpiece assembly (or ear tip) has a longitudinal axis and denotes the longitudinal axis of the earpiece assembly (or ear tip). For example, the axis of an earpiece assembly having generally cylindrical form is the assembly's central longitudinal axis.
Throughout this disclosure including in the claims, the expression “bearing” is used in a broad sense to denote a first element (e.g., unit 28 of FIG. 9, unit 128 of FIG. 13, or element 529 of FIG. 21) configured to support a second element (e.g., an ear tip) fitted onto the first element, such that the second element has freedom to rotate (“on axis,” where “axis” here denotes the first element's longitudinal axis) relative to the first element. Optionally also, the second element has freedom to pivot (“off axis”) relative to the first element. For example, one type of bearing is a ball joint unit (e.g., unit 28 of FIG. 9 or 10, or unit 128 of FIG. 13) having a ball portion, and configured to support an ear tip fitted onto the ball portion, such that the ear tip has freedom to rotate (“on axis”) and freedom to pivot (“off axis”) relative to the ball portion. Another exemplary type of bearing is an element (e.g., element 529 of FIG. 21) having a rotationally symmetric support portion (e.g., the partial conical end portion of element 529), said element being configured to support an ear tip that has been fitted onto it, such that the ear tip has freedom to rotate (“on axis”) relative to the support portion.
Throughout this disclosure including in the claims, the herein used expressions “sound tube” or “tube”, unless otherwise defined, generally refers a formed tube or tubes that are an integral part of the head piece portion of a complete stethoscope or other head piece assembly.
Stethoscopes are used by health care givers (primarily physicians, so that health care givers will be referred as such herein) to aid in the detection of body sounds for the purpose of diagnosing various symptoms such as heart beat anomalies or lung infections, etc. This procedure is commonly called auscultation.
In a class of embodiments, the invention pertains to a stethoscope earpiece designed to be inserted into a user's outer ear canal for purposes of efficiently transmitting sound from a remote stethoscope chest piece placed on a patient's body to the user's ear. The sound transmission is usually accomplished by one of two methods. The first and most common method is to utilize tube structures called lumens to connect the chest piece to the two ear pieces. Stethoscopes implementing this method are commonly called “acoustic” stethoscopes. The second method is to use an electronic chest piece with various sound sensing devices such as microphones. The sound sensing devices in the chest piece work with an electronic amplifier which then drives miniature loudspeakers that are generally placed in the earpiece assembly. Wires are used in the lumen to connect the speakers to the amplifier in the chest piece. A miniature loudspeaker may also be placed in the lumen structure or chest piece itself. This is well known in the art. Stethoscopes implementing this method are commonly called “electronic” or “active” stethoscopes.
Myriad devices are known in the art which attempt to improve the comfort and seal efficiency of stethoscope headpiece ear tips. Much of the art attempts to address the issues of ear tip softness, comfort of fit, ease of cleaning, etc.
The outer ear is the most external portion of the ear. The outer ear includes the pinna (the flesh covered cartilage), the ear canal, and the most superficial layer of the ear drum (also called the tympanic membrane). Portions of the ear after the ear drum such as the middle ear etc. are blocked from access to the outside world. The axis of the ear canal does not converge to the lower center of the head on the same plane as the ear canal, but rather converges slightly upwards and forward towards the upper bridge of the nose. This forward bend is roughly 10 to 15 degrees from the head's sideways horizontal axis (the Y axis in FIG. 3).
This is the reason why all good quality stethoscopes have the ear tips bent at approximately 10 degrees off the center line of the head piece. When placing the stethoscope headpiece on his ears, the physician instinctively knows to point the ear piece portions forward toward his face, i.e. the 10 degree angle is toward the back of his head. This orientation is clearly shown in FIG. 3.
The stethoscope ear tip generally fits into the distal portion of the ear canal, some 20 to 26 mm in length, whose proximal portion faces the ear drum. Depending on ear canal entry variations, the ear tip may penetrate 7 to 10 mm while deforming itself and the canal entry. Thus a seal is formed.
Once so positioned (with a seal), the ear tip is not in the position to rotate freely because of deformation and being out-of-center with reference to the imaginary ear canal rotation axes and the axis of the stethoscope headpiece arms. This will be explained in more detail in the body of this teaching.
Several devices which include rotatably mounted ear tips are described in the following references:
U.S. Pat. No. 6,514,213, to Moteki et al., describes a ball bearing in an earpiece assembly for ease of rotation. However it does not address the off axis angular changes due to the ear canal being set at an angle;
U.S. Pat. No. 5,002,151, to Oliveira et al., describes a ball and socket assembly, but in a fixed application designed for stationary hearing aids;
U.S. Pat. No. 3,710,888, to Peart, describes a rotatable sleeve assembly, allowing rotation of the ear tip in one axis, but not allowing off axis angular movement. This patent also describes an ear piece assembly including a rotatable ball, allowing rotation of the ear tip only on axis. No significant off axis angular movement is possible due to the assembly's design; and
U.S. Pat. No. 2,803,308, to Di Mattia, describes a rotatable sleeve assembly, allowing rotation of the ear tip in one axis. No off axis angular movement is possible.
U.S. Pat. No. 5,002,151 (Oliveira) describes (with reference to that patent's FIG. 4a) a hearing aid ear piece including the above-mentioned ball and socket assembly. However, the hearing aid is a stationary hearing aid and the ear piece is designed to remain fixed during use. The ball and socket assembly is designed to allow the ear tip to be easily attached and detached from the rest of the hearing aid, and is said to be a substitute for a bayonet attachment assembly. Oliveira thus teaches interchangeable use of a bayonet or ball and socket assembly for fixedly (but removably) attaching an ear tip to a hearing aid.
FIG. 4 is a cross section drawing of an earpiece described in the Moteki patent (U.S. Pat. No. 6,514,213) in which the inner race 6b of a ball bearing 5a is mounted on earpiece tube 8a, while the outer race 6c is fastened to a hub 6a which in turn is fastened to the ear tip 7a. This allows the ear tip to have free rotation about the ear piece axis as hub 6a rolls on balls 9a of bearing 5a. No provision is made for earpiece off axis movement.
FIG. 5 is a cross section drawing is shown of an earpiece described in the Peart patent (U.S. Pat. No. 3,710,888). This earpiece assembly uses a sleeve 5b screwed onto earpiece tube 8b. A second sleeve 6d is slipped over and swaged over distal end (the left end, in FIG. 5) of sleeve 5b. The swaging is loose, allowing “on axis” rotation of sleeve 6d over sleeve 5b (relative to the center axis of tube 8b). Sleeve 6d is fastened to ear tip 7b. This allows the ear tip 7b and sleeve 6d to rotate about the center axis of earpiece tube 8b. No provision is made for off axis movement of ear tip 7b or sleeve 6d. 
FIG. 6 is a cross section drawing of another earpiece described in the Peart patent. This earpiece assembly uses a ball 5c bonded onto earpiece tube 8c. Ear tip 7c is placed over the ball 5c, with freedom to rotate relative to ball 5c and tube 8c about the earpiece's longitudinal axis. Although the design allows “on axis” rotation of ear tip 7c (around the center longitudinal axis of tube 8c), the close fit of ear tip 7c's distal portion 9c around tube 8c would prevent significant off axis pivoting of ear tip 7c relative to tube 8c. 
Prevention of off axis pivoting of ear tip 7c was evidently a deliberate design of Peart in view of Peart's teaching at col. 1, lines 16-35, that although an ear tip could be mounted with unrestricted rotatability (about all axes) relative to the user's ear canal, restricted ear tip rotatability (rotatability only about an axis parallel to the ear canal's longitudinal axis) “suffices since it substantially eliminates, completely, tangential stress on the ear canal tissues. While this permits some stress to be exerted transverse to the axis of rotation, and along it, the usual movement of the stethoscope is not in such directions as would produce these types of stress, and, further, the ear canals are less vulnerable thereto.” The present inventor has recognized that this teaching of Peart is incorrect for a number of reasons, including the reason that, in some stethoscope users, the ear canal is very sensitive in all directions of stress and sustained pressure. The present inventor has addressed stethoscope user ear comfort issues in US Patent Application Publication No. 20090321196, published Dec. 31, 2009 (entitled Asymmetric Tension Adjustment Mechanism and Head Piece including Same), and the present invention addresses such comfort issues in a very different way to be described in detail below.
Peart notes at col. 1, lines 21-27, that ear tips can be connected to sound tubes “by ball and socket joints, so that when the eartips are in place in the ear canals, the axis of rotation between sound tubes and eartips can have any angular orientations whatsoever.” However, Peart does not suggest that there should be any limitation on the range in which an ear tip should be allowed to rotate about any particular axis. In contrast, the present inventor has recognized that although, for practical use, a full range of axial (“on axis”) rotation of an ear tip can be allowed over the full range (i.e., by any amount from 0 to 360 degrees about the axis of an ear piece assembly to which the ear tip is mounted), and the ear tip should be allowed significant freedom to pivot off axis as well as on axis, the ear tip's off axis deviation should typically be limited to be not be more than about ten degrees (relative to the axis of the ear piece assembly). The reason for this is that if an ear tip moves (e.g., is bent) off axis too far, it becomes cumbersome to insert into the ear canal. Additionally, it can easily fall off its socket when inadvertently rubbed up against clothing, coat pockets, or other objects.
Typical embodiments of the present invention achieve desirable (substantial, but limited) ear tip off axis rotatability, and substantial (preferably unlimited) “on axis” rotatability, by splitting up the functions of ear tip rotation and off axis movement restriction. This will be further explained in detail below.